KA Stroker

[Tatanko]

I posted this in another forum, but didn't get much of a response. And I figured I'd get better, more intellegent responses in the KA-T forum. Anyways, I was thinking of ways to increase the displacement cheaper than boring out the block and paying tons of money for oversized pistons. But of course we all know the KA only comes in one displacement. So I started looking around at other Nissan engines with the same bore to see what their stroke was and if I could potentially use that to increase the KA's stroke. Well, the only match is the QR25DE. This increases the stroke from 96.00 to 100.00. My question is, would it be possible to use the QR's crankshaft and rods (pistons also?) in the KA to create a stroker engine? The only concern I have is that you might have to limit your redline like another 500 RPM's or so due to the increased stroke, plus the fact that the bore and stroke are so far apart. SO...does anyone have any input?

Also, don't refer me to KAJosh, who made a 2.5L by boring out the block and using larger pistons. That's not what I'm trying to accomplish.

[skatanic28]

the ka is already a pretty undersquare motor. it does pretty good for me down low, i think most people want to improve on its high end.

anyways...i think the ka has more in common with the old inline 6's nissan made then the new qr.

[Tatanko]

Inline-6's would be useless. You can't use a crankshaft from any 6-cylinder engine in any 4-cylinder engine...it's common sense that it'd be too long, wouldn't line up, and has 2 extra spots for rods.

[skatanic28]

Inline-6's would be useless. You can't use a crankshaft from any 6-cylinder engine in any 4-cylinder engine...it's common sense that it'd be too long, wouldn't line up, and has 2 extra spots for rods.

i was talking about cylinder spacing.

[Drift Machine]

I believe there is a stroker kit for the KA that turns it into a 2.6 liter, it was made by a company called flat land racing. But last time I remember seeing it was a long long time ago and a search on Google yeilded nothing.

[SHIEF]

Your not going to be paying that much more for .10 or .20 over pistons. Also it's not that much to have the cylinders bored either. Not to be a d!ck, but it's really not necessary to stroke this engine, just bore it a little and be done.

[Tatanko]

Sorry skatanic28, I misinterpreted what you said. I apologize. As for that 2.6L...that sounds awesome. However, doing a search, I found a company called Flatlander Racing which is what I think you meant. However, they only have stroker kits listed for Ford's, Chevy's, and Chrysler's.

I'm liking the sounds of this...combined, I could have a 2.7L KA

[Drift Machine]

http://www.importperformancepa....html

Apparently one is coming out for the E.

[SeVa-S13]

Why stroke an already stroked engine?If you want more power, it'd be cheaper to just grab some forged internals and increase the boost pressure. If you want that "low-end grunt," get a better spooling Turbo (read:Ball Bearing instead of the archaic but still good T3/T4), which performs well all over the RPM range. Stroking it just seems like a such a hassle and an expensive and back asswards way of getting more power.

[masticatingcow]

I'm liking the sounds of this...combined, I could have a 2.7L KA

Yeah, and you can wait 30 seconds to reach your powerband... J/K.

From what I understand, the immediate benefit of stroking an engine (in a turbo application) would be to accelerate exhaust gases and limit turbo spool time. I'm not 100% on that concept, but assuming I'm more or less right...

The KA is already an oversquare engine, meaning the stroke is longer than the bore is wide. It already has the "advantage" high piston speeds to accelerate exhaust gas quickly. This combined with the availablity of VERY low-lag turbos makes me question the necessity of stroking the KA. I concur with SeVa-S13 in wondering what your intent is with it...

Of course, we're all assuming that you are turboing your KA because this post is in the KA-T forum. If you wanted to stick with N/A tuning, then we can all agree that you're operating on the principle that displacement buys you power. (And REAL power aka torque, not arbitrary power aka HP)

Oh and Tatanko, the KA series is not limited to the 2.4L engines. The Nissan Caravan (never released in US) used/uses a 2.0L version of the KA, aptly called the KA20DE.

[Tatanko]

My intent is to eventually turbo the engine, but that has nothing to do with increasing the displacement. They are two different subjects in this case. My intent was to merely increase the displacement. More displacement (in most cases) = more power. But since everyone is telling me no, you can't stroke it cheaply, then I'm not going to.

Oh and Tatanko, the KA series is not limited to the 2.4L engines. The Nissan Caravan (never released in US) used/uses a 2.0L version of the KA, aptly called the KA20DE.

I did not know that. You see, a colleague and I run a website called Powered by Nissan, and our main feature is a list of all Nissan, Infiniti, Datsun, and Prince engines. Of course, we don't all know everything, so I guess I need to make an addition to the KA section If you could take a look at the list and see anything missing, by all means, tell me of more engines.

[Red-KAT]

I think you should keep looking into the stroked KA idea...

Who cares if it has a long stroke... more is better!

Was it not a strokes SR20 that was 2.2l and made 700hp?

But also another thing is... Some high HP cars have a very short stroke... with a wide pistone so they can rev very high.

By stroking an engine it raises compression right? I mean you cant go down farther if you dont go up farther...

Sorry if any of that is stupid.

[GlacierFreeze]

Stroking only increases dislpacement.

Milling the head, using different sized head gaskets, and using different CR pistons change compression.

edit... Think of it this way, the crank is going to be shaped differently than your stock crank. It's going to allow your rod and piston to be pulled down further away from your head, and it allows more air and fuel to be packed in the cylinder. CR won't change because the piston stops at the same point as before.

[masticatingcow]

Most of the resources about this engine are in Japanese, so unless you can read Japanese or have a good translator, you'll be in the dark about MOST of it...

What I can comfirm is that the engine DOES exist, that it is used in what appears to be a base model van and that it is/was available in Nissan/Datsun trucks in Japan. The KA24DE is/was offered as an option, as was the 3.0L deisel engine. Surprisingly, searching through Google yields quite a few hits. Unsurprisingly, many of them are instances on message boards when users mistyped "KA24DE" in reference to the 240sx.

http://members.aol.com/Carsofjapan/dats ... /n...n.htm

Red-KAT, you are right in saying that stroking the motor will give an increase in power, though you have to remember that it will come at the cost of engine responsiveness. In speed contests, be it drag racing, auto-x, drifting or whatever, huge power is worthless unless it is relatively easy to get to, you know?

[S13ChucKAT]

I am not all quite to sure, but the KA24E/DE has multiple combinations of parts you can mix and match.. and end up with a 2.8 liter..

I believe its something like the Crank, and rods out of a Mexico made KA24E truck motor, and the DE pistons from a USA 240sx.. using a KA24E block.. i forget the combo.. but it gets up to 2.8

[andrave]

the only one I know who has attempted something like that used something like a nissan 2.0 liter, I think its an f20 block, and then used mitsubishi crank and 350 v8 rods...

[Tatanko]

Thanks for the continued responses guys. S13ChucKAT, I seriously doubt it. All KA24's use the same bore and stroke. As for the internals being different, they would still have to be the same size. There aren't "different" KA24's that accomplished 2.4L through different ways, they're all the same.

[S13ChucKAT]

ermmm no, something about the mexican made KA24 was different.. or.. wait.. isnt it like.. L20.. i think it was called the L20... it had the rods/pistons.. Blah. let me

[Tatanko]

Hmmm...I doubt it. The L20 has a shorter stroke and a smaller bore than the KA.

(78.00 x 69.70 versus 89.00 x 96.00)

[ahbongkeo]

Stroking only increases dislpacement.

Milling the head, using different sized head gaskets, and using different CR pistons change compression.

edit... Think of it this way, the crank is going to be shaped differently than your stock crank. It's going to allow your rod and piston to be pulled down further away from your head, and it allows more air and fuel to be packed in the cylinder. CR won't change because the piston stops at the same point as before.

im confused.....if the rods and pistons are pulled further away from the head to allow more air and fuel to be packed into the cylinder, then how can it still stop at the same place as before?

[Tatanko]

im confused.....if the rods and pistons are pulled further away from the head to allow more air and fuel to be packed into the cylinder, then how can it still stop at the same place as before?

Good point

[Redline240]

Your crank would be different, the rod would be further from center and by using a shorter piston/rod combo it would still stop at the same distance from the head but would go further down the cylinder...i think, haha

Redline

[Red-KAT]

EDIT: Deleted... I'm just in a pissy mood.
Modified by Red-KAT at 4:50 AM 9/9/2004

[SeVa-S13]

The predessor of the Ka, called the Z24, has some similar bits and has been used in conjunction with KA's to make some interesting hybrids. Mostly, people DETSROKE the KA so they can make more power out of it. Power is a combination of torque and RPMs.

Most high power and efficient NA engines use short stroke, large bore desings, much like motorcycles. (well, atleast crotch rockets anyways)

Let's take out modern 350 for example. I believe the C5 Z06 engines make a very impressive 405bhp. That's nice and all, but that's barely ahead of engine technology and eficiency that was achieved in the 60's. Hmm...that's odd. Wait no it's not! It's the same damn design and tech. (Whack) 405 hp out of 350ci = ~1.16hp per ciKA24DE = ~1.07 hp per ci

Ok, now let's see, both engine has good torque delivery and a relatively broad powerband but lack a bit up top, and neither being able to rev very well, yet one is supposed to be the premier perfromance engine for america's most popular sports car and the other is a modified pickup engine slapped into a sports coupe to pacify the potential woman buyers. Something's wrong there.

Now let's look at a much better designed, higher revving engine made for racing, not driving Susy to girl scouts and Bobby to football practice.An NSX for example sports a 3.2l DOHC, high revving V6, producing 320bhp (100hp per liter, a good measuring mark for modern engines I'd say). Its hp to cu ration is well in excess of 1.6 and it was designed in the late 80's and early 90's. We're almost a decade and half past that--I think it's time we got past torque is the be all and end all of power. We're trying to go fast here, and race cars produce power where? All over the RPm band, especially the upper half. Leave the lopsided torque numbers for the diesel trucks and 454's.

[Tatanko]

If that's implying the 240SX is a "sports car" then I don't even know what to say to that...

I'll give it to you seva, you have good ways of getting your point across. I also very highly respect your opinions, since you're one of the very few people I see on these forums that actually, GENUINELY seems to know what they're talking about sometimes.

I agree, lop-sided torque numbers belong in trucks and huge V8's. Your thinking of sporty cars/sports cars best being off with a very balanced powerband is a good idea, but it's hard to achieve something like that. I think what you fail to see was my goal in increasing the displacement of the engine. My goal wasn't huge torque numbers, it was merely to increase the engine's ability to create both horsepower AND torque.

Although honestly, before I started this thread, I wasn't the most enlightened person on the effects of stroking and boring the engine (the effects each can have). Now that I understand better, I can adjust my plans a bit. Just saying this so you know that I'm not ignoring what you're saying or anything.

So, since stroking the engine wouldn't be a good idea (which it worried me to begin with anyway due to the stroke already being larger than the bore), what can anyone suggest to me as far as boring it out? From what I've found on sites that sell overbore pistons, it's generally just 0.5mm over. And truly, to increase the displacement even a full 100cc's, don't I need 1mm? Even so, I'm looking to increase the bore enough for 200cc's (or close to it), so how can I accomplish that? Would custom pistons need to be ordered from somewhere? Would you even think it's a good idea to raise the bore that much, or will there be negative side effects?
Modified by Tatanko at 7:33 AM 9/9/2004

[masticatingcow]

Have you ever looked at the KA block? There's really not a whole lot of room for overbore. IF you were able to pull it off, I'm almost positive you'd have to order custom hardware, be it pistons or rods or something... I couldn't tell you for sure.

SeVa-S13, so what you're saying is that destroking the KA yeilds power... If we drop the displacement of the KA to say, even 2.3L, then that would improve high-end breathability, right? Would it then be easier to extract some top end numbers using the same tuning techniques applied to the 2.4L engine?

What we're all trying accomplish is more power. We know we have 2.4L to work with, and if the "modern" benchmark is 100HP/liter, then we're aiming for about 240HP at the crank.

Well, it's been done. It's not cheap and it certainly takes some work, but that KA24DE HAS been tuned to perform like a modern sports engine.

[Red-KAT]

Is there a way to destroke the engine and get the same compression...

Ya know just make it all shorter...

I think the weight loss of the internal items would help the Rev factor out quite a bit.

I want to turn this engine into a small version of an RB... Short stroke.

[DSMs_Suck]

to destroke and keep your existing compression ratio your best bet is to get custom pistons. If you destroke they will likely put more material on the piston and move the wrist pin down a few mm.

Murray

[masticatingcow]

Which RB are you thinking about Red? If you want a high-revving short stroke engine with lots of potential, maybe consider a RB20DET swap... it's pretty cheap, and with some minor modifications, fits right in. It might be cheaper than destroking the KA, now that I think about it... hmm...

[Red-KAT]

Engine swaps are the best way for us to make real power... And I'm not talking the SR20...

Swapping to any RB20 - RB25 or RB26 will be a huge jump in engine.

I would like to purchase an S13 and move my engine to it and then build an RB for my S14

Is there a way to get a custome crank? to shorten the stroke?